Hmm. otool tells me it's not linked against it:

     ~  otool -L /usr/local/sbin/mtr
    /usr/local/sbin/mtr:
     	/usr/lib/libresolv.9.dylib (compatibility version 1.0.0, current version 1.0.0)
     	/usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 1197.0.0)
     	/usr/lib/libncurses.5.4.dylib (compatibility version 5.4.0, current version 5.4.0)